Vibratory compactor

ABSTRACT

A vibratory compactor including a housing having vibratory means therein and for engaging the ground to compact the same, and a self-leveling support for the housing including spring means, a mounting device adapted to be connected to the lift arm of a vehicle, and means for compressing the springs whether the mounting device is moved upwardly or downwardly by the lift arm. The vibratory means include a pair of spaced shafts bearing eccentric weights and a motor within the housing for driving the shafts in a manner to cause vertical oscillation of the housing. The drive includes a chain extending from the motor to the underside of one of the shafts and to the top side of the other shaft and thence back to the motor to rotate the shafts in opposite directions.

[151 3,635,132 [451 Jan.1's,197z

United States Patent Mcllrath et al.

[72] lnventors: William P. Mcllrath; Chris Stougaard,

both of Racine, Wis.

Rex Chainbelt Inc.

Sept. 22, 1969 Primary Examiner-Jacob L. Nackeno` ['73] Assignee:

[22] Filed:

Attorney-Hofgren, Wegner, Allen, Stellman & McCord ABSTRACT [21] Appl. No.; 859,933

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pair of spaced shafts bearing eccentric weights and a motor within the housing for driving the shafts in a manner to cause vertical oscillation of the housing. The drive includes a chain extending from the motor to the underside of one of the shafts and to the top side of the other shaft and thence back to the motor to rotate the shas in opposite directions.

16 Claims, 5 Drawing Eigures l0 mm wmmmdr. mmwmm i i VHCCBPB 00.12569 4666666 9999999 1111111 9593552 3881229 9356423 OAndw 48141137 13020052 2,9,0,0,l,2.4, 2233333 VIBRATORY COMFACTOR BACKGROUND OF THE INVENTION Construction and excavation personnel have long relied upon the use of tampers or Compactors for compacting loose till in construction areas for any of a variety of reasons. The normal progress of the art has resulted in provision of compactors of substantial size for accomplishing the compacting jobs at a more rapid rate.

Such large compactors are typically mounted on vehicles of one sort or another and quite often, to lift arms thereon. For example, it is quite common to mount a compactor on the socalled backhoe of a tractor.

Quite frequently, such compactors include spring mounting devices for absorbing oscillation produced in the compacting device before it is passed onto the vehicle and perhaps to permit some degree of self-leveling. However, the spring mounting devices heretofore known have been constructed such that the springs used therein are placed under compression when the compactor is pressed against the ground and are placed under tension when the unit is lifted from the ground. lf such spring devices are properly constructed, they may not be overloaded when pressure is applied to the compactor for holding the same closely against the ground, but, when under tension, they can be subject to overload and may break thereby injuring the operator of the unit as well as workmen in the immediate vicinity of the same. Furthermore, when springs are frequently placed under tension, their life is decreased.

Another drawback of the prior art constructions is that the same do not permit any great degree of self-leveling. Typically, such prior art devices, when used with the backhoe, require that the operator regulate the attitude of the compactor with respect to the horizontal by operating the bucket cylinder of the backhoe to change the attitude of the compactor.

Additionally, such constructions, due to the interposition of thesprings between Compactors and the vehicles, tend to permit a great deal of sway of the compacting unit at the end of the support arm when movement of the same by the support arm is stopped or started abruptly.

Finally, the means used to cause vertical oscillation in such Compactors, typically consist of a pair of shafts bearing eccentric weights together with appropriate gearing and idlers and a drive means to cause the shafts to rotate in opposite directions. Use of such gears and idlers, because of the relative precision required in the forming of the same, increases the expense of such devices.

SUMMARY OF THE INVENTION The instant invention seeks to provide a new and improved vibratory compactor and mounting means therefor which overcomes those difficulties mentioned above so typical of the prior art devices. In the exemplary embodiment, spring means are operatively associated with the compactor and a mounting device by which the compactor is to be secured to the lift arm or the like on a vehicle. Means are provided so that the springs are always placed in compression no matter whether the mounting device is moved upwardly or downwardly by the lift arm. As a result, the life of the springs is significantly extended over that of the springs in the prior art devices because the springs are never placed in tension. By the same taken, since the means always place the springs in compression, they may be constructed so as to bottom out (i.e., adjacent convolutions in contact with each other) whereby they cannot be overloaded to the point that they break and injure the operator or the bystanders.

The foregoing is accomplished by means of two sleeve elements which are movable towards each other on the reduced diameter portion of an elongated shaft extending upwardly from the compactor housing. A coil spring surrounds the shaft and is interposed between the sleeve elements. Abutments are associated with the mounting device so that when the mounting device is moved upwardly, the lowermost sleeve is moved upwardly and the uppermost sleeve is maintained stationary while the spring is compressed. By the same token, when the mounting device is moved downwardly, the uppermost sleeve is moved downwardly while the lowermost sleeve is maintained stationary to again compress the spring.

Furthermore, a housing for the spring is provided as a safety measure.

In the exemplary embodiment, the mounting device comprises a pivot pin which is centrally located with respect to the compactor and to preclude swaying of the compactor unit during movement of the arms to which it may be secured, a connecting means is secured to the compactor at a location spaced from the pivot pin and includes a cable which may extend to the bucket cylinder or comparable device found on left arms such as a backhoe or the like.

Finally, in order to provide a long-lived and relatively inexpensive compactor device, vibratory means without gears or idlers are provided. In the exemplary embodiment, there are provided two generally parallel shafts each bearing `eccentric weights and a hydraulic drive motor; and all three are located within a closed housing including a compacting plate. A chain engaged with the sprocket on the output shaft of the hydraulic motor then is engaged with the lowermost side of the sprocket associated with one of the two weight-bearing shafts and with the top side of the sprocket with the other weight-bearing shaft and then returned to the sprocket of the drive motor. The arrangement provides for rotation of the drive shafts in opposite directions and yet totally eliminates the need for idlers and permits the use of relatively inexpensive sprockets as compared to more expensive gears.

Other objects of the invention will become apparent from the following specification taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. l is a side elevation of a compactor made according to the invention mounted on a backhoe borne by a vehicle and in an elevated position with respect to the ground;

FIG. 2 is a fragmentary side-elevational view illustrating the backhoe with the compactor in a ground-engaging position;

FIG. 3 is an enlarged side elevation of the compactor with parts shown in section for clarity;

FIG. 4 is a vertical section illustrating spring means and associated structure lwhen the backhoe is operated to lift the compactor; and

FIG. 5 is a vertical section of the spring means and associated structure when the backhoe is operated to apply downward pressure to the compactor.

DESCRIPTION OF THE PREFERRED EMBODIMENT A vibratory compactor made according to the invention is illustrated as being suspended from a backhoe, generally designated l0, borne by a vehicle l2 which is only partially shown. The backhoe l0, as is well known, includes a first arm 114 pivotally mounted to the vehicle l2 and movable with respect to the same by a power cylinder not shown. At the extreme end of the arm 14, the backhoe pivotally mounts a second arm 16 and it is at the extremity' of the arm 16 that the compactor, generally designated 18, is mounted. As will be seen, the connection is a pivotal one and for the purpose of moving the compactor 18 about the pivotal mount, connecting means, generally designated 20, mounted on the compactor 18 and including a flexible cable 22 are secured to the piston 24 of the bucket cylinder 26 of the backhoe l0. Those skilled in the art will recognize that the bucket cylinder 26 is conventionally present on a backhoe for the purpose of changing the attitude of a bucket (not shown) normally pivotally mounted to the extreme end of the arm 16.

As viewed in FIG. l, the piston 24 of the bucket cylinder 26 is retracted and through the cable 22, has drawn the compactor 18 in a counterclockwise direction about the pivot on which it is connected to the arm 16.

Turning now to FIG. 2, it can be seen that when the bucket cylinder 26 is operated to extend its piston 24, the cable 22 will go slack and permit the compactor 18 to pivot to a generally horizontal attitude with respect to the arm 16 of the backhoe for compacting purposes. It will be further observed that with the bucket cylinder 26 in the position illustrated in FIG. 2, substantial rotation of the compactor 18 about the pivot by which it is connected by the anns 16 and away from the horizontal position illustrated may be accommodated by the cable 22 so that rather abrupt changes in terrain may be accommodated by the compactor 18. That is, the attitude of the compactor 18 with respect to the backhoe 10 and thus the vehicle can be changed substantially due to the slack in the cable 22 when the bucket cylinder 26 is extended.

Turning now to FIG. 3, the compactor is seen to comprise a housing, generally designated 30, which may be constructed in any suitable manner to provide a sealed enclosure to preclude entry of dust or other foreign matter. The housing 30 terminates in a platelike underside 32 which is adapted to engage the ground for compacting purposes.

Vibratory means, generally designated 34, are mounted within the housing 30 for the purpose of imparting vertical oscillation to the same, whereby the plate 32 will be oscillated in a vertical direction to compact the ground on which it is resting. The Vibratory means 34 include a conventional hydraulic motor 36 which may receive hydraulic fluid under pressure through a fitting 38 from a hydraulic pump normally found on vehicles of the type on which the compactor may be mounted and which may further return expended hydraulic fluid to the vehicle by any suitable means not shown.

The motor 36 includes an output shaft on which a drive sprocket 40 is mounted. The sides of the housing 30 mount bearings 42 and 44 which are horizontally spaced from each other, and which mount for rotation, a pair of shafts 46 and 48 respectively. The shaft 46 mounts an eccentric weight 50 while the shaft 48 in tum mounts an eccentric weight 52.

Shaft 46 also mounts a drive sprocket 54 while the shaft 48 mounts a drive sprocket 56. Finally, there is provided a chain 60 which extends from the drive sprocket 40 associated with the hydraulic motor 36 to the underside of the drive sprocket 56 and thence to the top side of the drive sprocket 54. From the drive sprocket 54, about which the chain 60 is about halfway trained, the same is returned to the drive sprocket 40. As a result of the foregoing construction, it will be appreciated that when the hydraulic motor 36 is energized, the shafts 46 and 48 will be rotated in opposite directions.

As viewed in FIG. 3, the weights 50 and 52 are directed towards opposite sides of the irrespective shafts, and in a horizontal direction. Thus, when the shafts 46 and 48 are rotated in opposite directions, according to the mechanical arrangement mentioned in the preceding paragraph, the eccentric weights 50 and 52 will be moving upwardly simultaneously and downwardly simultaneously but will be moving in opposite horizontal directions at all times. Thus, by balancing the rotary elements associated with the shaft 46 and those associated with the shaft 48, only Vibratory forces in the vertical direction will be present.

In order to secure the housing 30 to the backhoe arm 16, there is provided a mounting device, generally designated 62 which includes a pair of spaced, apertured, upstandng ears 64 (only one of which is shown) which are mounted on respective plates 66. Aligned apertures in the ear 64 are adapted to receive the pivot pin 68 which may extend through an appropriate aperture in the extremity of the backhoe arm 16 and which with the plates 66, define a generally H-shaped member. Retaining means such as washers 70 and a cotter pin 72 may be employed to maintain the pivot pin 68 within the apertures. As a result, the compactor may pivot about the axis provided by pivot pin 68 with respect to the vehicle.

As mentioned above, an l-l-shaped member is formed and the arrangement is such that the pivot pin 68 forms the crossbar of the H, The plates 66 are, in turn, centrally mounted by means to be described in greater detail hereinafter over the housing 30 so that the pivot axis provided by the pivot pin 68 is centrally located with respect to the housing 30 and because, as will be seen, the compactor is generally symmetrical in its construction, the same will tend to assume a horizontal attitude about the pivot axis provided by the pin 68.

Spaced from the pivot pin 68 and secured to one end of the plates 68, is an apertured ear 73 to which the cable 24 may be secured.

At each end of the plates 66 there is provided an aperture 74 (only one of which is shown in FIG. 3) which receives a bearing member 76. An elongated shaft 78 extends through the bearing member 76 in a generally vertical direction from the housing 30 and includes a reduced diameter portion 80 intermediate its ends. To form the reduced diameter portion 80, two enlarged diameter sleeves 82 and 84 may sandwich a lesser diameter sleeve 86 and be located in the described position by a retaining rod 88. The' retaining rod 88 terminates in its threaded end 90 which may receive a nut 92 for retention of the sleeves.

Normally surrounding the reduced diameter portion 80 is a generally cylindrical housing 94 which is secured by any suitable means to the respective end of the plates 66. The upper end of the housing 94 includes an end member 96, which again may be secured to the housing 94 by any suitable means, and which includes a bore 98 receiving a bearing 100 which is similar to the bearing 76. The sleeve 82 is, in turn, received within the bearing 100.

The end member 96 may also include a bore 102 associated with an oilcup 104 so that lubricants may be provided to the bearing 100. Similar provision for the lubrication of the bearings 76 (not shown) may be provided.

Reciprocally mounted about the lower end of the upper sleeve 82 is a first sleeve element 106 having an inturned lower end 108. Similarly, mounted about the upper end of the lower sleeve 104 is a second sleeve element 110 having an upper inwardly directed end 112. The arrangement of both the sleeves 106 and 110 is such that free movement of the sleeve element on the respective sleeve forming the shaft 78 is permitted except when the inturned end 108 or l 12 is in abutment with the end of the sleeve 82 or 84 on which the sleeve element rides. As a result, andiin the case of the first sleeve element 106, the same may move downwardly from 'the position shown in FIG. 3 but not upwardly therefrom. In the case of the sleeve element 110, the same may move upwardly from the position shown in FIG. 3, but not downwardly.

The uppermost end of the sleeve element 106 may abut the end member 98 of the housing 94 as illustrated in FIG. 3, and the lower end of the sleeve element 110 may similarly abut the plate member 66 in certain instances as will be seen hereinafter. The construction is completed by a coil spring 114 which is wound about the reduced diameter portion 80 of the shaft 78 and interposed between the sleeve elements 106 and 110. The arrangement is such that whenever one of the sleeve elements 106 or 110 is moved towards the other, the coil spring 114 will be compressed.

As will be seen, the spring 1 14 may be compressed until the same bottoms out, i.e., adjacent convolutions are in contact with each other and at such a time one or the other of the sleeve elements 106 and 110 may no longer be in contact with its respective one of the sleeves 82 or 8 4 forming the shaft 78. Thus, in order to preserve alignment of the sleeve element 106 or 110 with respect to the sleeves 82 and 84 forming the shaft 78, the inwardly directed ends 108 and 112 of the sleeve elements 106 and 110 respectively, are formed to contact the sleeve 86 forming the reduced diameter portion of the shaft 78. Thus, if the sleeve element 106 is moved downwardly and off of the sleeve 82, sleeve 86 will guide the end portion 108 so that when the sleeve element 106 is returned upwardly, it will again circumscribe the lower end of the sleeve 82.

ln the exemplary embodiment, four of the shafts 78 and associated structure are provided and the same are located symmetrically about the pivot axis defined by the pivot pin 68. ln order to secure the shafts 78 to the housing 30, there may be provided a block lll) having a recess i122 therein terminating in a bore l24l which receives a reduced end B26 of the sleeve iid. The retaining rod db may include an enlarged head t28 which is received within the recess i122 but is of sufficiently large size so that the same will not pass through the bore B24. Packing material i3@ may fill that portion of the recess ll22 which is not occupied by the reduced end i216 of the sleeve 8d or the head 112@ of the retaining rod dii.

The block llftli may then be secured to the upper side of the housing 30 as by bolts lidi) or the like. As a result, the shafts 78 and the associated elements described previously are secured to the compactor housing 3l) so that when the lift arm i6 of the backhoe lltl is manipulated, the raising of the H-shaped member including the plates 66 will ultimately cause the lifting of the housing 3U.

Turning now to FIGS. d and 5, the manner by which coil springs lli'l are maintained under compression irregardless of whether the compactor is being directed into the ground by the backhoe or removed therefrom, will be illustrated therein. FIG. 4 illustrates the arrangement when a lifting force is applied to the mounting device. In such a case, the plate 66 is moved upwardly on the shaft 78 and the same abuts the lower end of the second sleeve element 110. Thus, the latter is moved upwardly thereby moving the lower end of the spring 114 upwardly. At this time, the upper end of the spring M4 cannot move in view of the fact that upper movement 0f the first sleeve element M18 is restrained in the manner mentioned previously, and as a result, one end of the spring lllld is moved towards the other. This results in the same being placed under 4compression even though the device is being lifted upwardly.

As illustrated, the spring 114i has bottomed out and further loading is impossible.

When downward pressure is applied, the plate 66 is moved downwardly and by virtue of the connection of the same to the end member 9b through the housing 9d, the end member 96 will engage the upper end of the first sleeve element 10b to move the same downwardly. As a result, the upper end of the spring ltd will move downwardly but inasmuch as the lower end of the spring iid cannot move in view of its contact with the second sleeve element lli() which is maintained stationary in such instances in the manner described previously, spring 114 will again be placed under compression.

From the foregoing, it will be appreciated that a compactor made according to the invention provides means whereby springs used to secure the compactor housing to a lifting arm or the like, are maintained in compression for both upward and downward application of force to the compactor. As a result, the life of the springs 114 is significantly extended thereby lowering the maintenance cost of the device. Furthermore, the arrangement is such that the loading of the springs 114 will merely cause the same to bottom out so that the springs will never be overloaded.

The provision of the housing 94 insures that, if for some reason a spring is defective or breaks, the personal adjacent the device will not be injured.

The construction of the various mounting elements and the provision of the spring mount, insure that the device will be self-leveling so that there will be no need for an operator of the device to operate a bucket cylinder on a backhoe or equivalent power device on the other type of apparatus, to conform the compactor to the terrain.

Additionally, the use of the unique vibratory means provides for a reliable and economical construction that avoids the expense attendant to the use of idlers and gears.

Finally, the use of the flexible connecting means including the cable 22 in conjunction with the bucket cylinder of a backhoe pennits the compactor to be raised with respect thereto without a great deal of sway due to abrupt starting and stopping of the vehicle or support arm.

Having described a preferred embodiment of our invention, we do not wish to be limited to the details set forth, but rather, to have the same construed according to the following claims.

We claim:

ll. A vibratory tool comprising a tool adapted to perform work when vibrated, vibrating means associated with said tool for oscillating the same in a predetermined direction, a mounting device adapted to be secured to a vehicle, spring means operatively interposed between said mounting device and said tool, and means for placing said spring means under compression whenever a force directed either way in said direction is exerted against the mounting device; said spring means comprising a spring having two ends and being compressible by moving one end toward the other, and said placing means comprising a first element engaged with one end of said spring means and a second element engaged with the other end of said spring means, means connected to said mounting device for moving said second element toward said first element to compress said spring means when said mounting device is moved one way in said direction and means for moving said first element toward said second element to compress said spring means when said mounting device is moved the other way in said direction.

2. A tool according to claim l wherein said iirst element comprises a sleeve mounted for limited movement on a shaft from a stopped position toward said second element, and said second element comprises a second sleeve mounted for limited movement on said shaft from a` second stopped position toward said first element; said spring means comprises a coil spring wound about said shaft and interposed between said first and second sleeves and said means connected to said mounting device both comprises abutments for engaging their associated sleeves.

3. A tool according to claim 2 further including housing means surrounding said sleeves and said spring.

d. A tool according to claim 2 wherein said shaft includes a center portion of reduced diameter, and said first and second sleeves are movable towards each other within the contines of said portion of reduced diameter.

5. A tool according to claim l wherein there are a plurality of said last-named means symmetrically located about said mounting device.

6. A vibratory tool comprising a tool adapted to perform work when vibrated, vibrating means associated with said tool for oscillating the same in a predetermined direction, a mount ing device adapted to be secured to a vehicle, spring means operatively interposed between said mounting device and said tool, and means for placing said spring means under compression whenever a force directed either way in said direction is exerted against the mounting device; said tool comprising a compactor especially suited for use with a vehicle having a pivoted backhoe arm including a bucket cylinder and wherein said mounting device comprises a pivot adapted to be pivotally secured to the extremity of the backhoe arm; and further including connecting means secured to said compactor at a location spaced from said pivot including a flexible cable adapted to be secured to the bucket cylinder.

7. A vibratory compactor comprising: a housing including a bottom plate adapted to engage the ground to compact the same, spring-loaded mounting means secured to the upper side of the housing and adapted to be secured to a vehicle so that the compactor may be moved along various terrain by the vehicle, and means for oscillating said housing in a generally vertical direction comprising a pair of parallel shafts within said housing and each mounting an eccentric weight, said shafts being oriented with respect to each other so that when driven in opposite directions their respective weights will be moving in the same generally vertical direction but in opposite generally horizontal directions, a motor having a rotary output shaft within said housing, and a chain in driving relation with said output shaft and in driving relation. with said shafts, said chain having one run thereof engaged with one of said shafts at approximately the underside thereof and with the other of said shafts at approximately the top side thereof whereby said shafts may be driven in opposite directions.

d. A compactor according to claim 7 further including a mounting device operatively associated with said housing and adapted to be secured to a vehicle, a means associated with said spring means and said mounting device for compressing said springs regardless of whether said mounting device is moved upwardly or downwardly.

9. A compactor according to claim 7 further including a mounting device comprising a pivot centrally located on the top of said housing and connecting means secured to said housing at a location spaced from said pivot and including a cable adapted to be secured to a bucket cylinder of a backhoe whereby a bucket cylinder may be used to pivot the compactor housing about said pivot point to raise or lower the same.

l0. A self-leveling, vibratory compactor comprising: a compacting plate adapted to engage the ground; vibrating means associated with said plate for oscillating the same in a generally vertical direction; a mounting device adapted to be secured to a lifting arm on a vehicle; and means interconnecting said mounting device and said compacting plate including a plurality of shafts having one end connected to said compacting plate, each of said shafts having a reduced diameter portion intermediate its ends, a coil spring mounted about said reduced diameter portion, opposed sleeves abutting opposite ends of said coil spring and movable towards each other along said reduced diameter portion, and spaced abutments associated with each of said shafts and secured to said mounting device, said abutments including a first abutment for moving one of said sleeves towards the other of said sleeves when said mounting device is moved downwardly and a second abutment for moving said other sleeve towards said one sleeve when said mounting device is moved upwardly whereby said coil springs will be compressed regardless of the direction of movement of said mounting device.

11. A self-leveling vibratory compactor according to claim l1 wherein said compacting plate is defined by the lower side of a generally closed housing, and said vibrating means are located within said housing and further comprise first and second, generally horizontal, spaced rotary shafts, means mounting said shafts for rotation, eccentric weight means mounted for rotation with each of said shafts and a drive motor including a rotary output shaft and a flexible, endless drive member associated with said output shaft and drvingly engaging the underside of one of said rotary shafts and the top side of the other of said rotary shafts to rotate said rotary shafts in opposite directions.

l2. A compactor according to claim l wherein said mounting device further includes means defining a generally horizontal pivotal mount for connection to a lift arm of a vehicle and further including means secured to said mounting device at a location spaced from said pivot mount and including a flexible cable adapted to be operatively secured to a power cylinder associated with the lift arm.

13. A vibratory compactor comprising: a housing including a plate adapted to engage the ground to compact the same, and means for oscillating said housing in a generally vertical direction to compact the ground with which said bottom plate may be engaged and comprising a pair of parallel shafts in said housing and each mounting an eccentric weight, said shafts being oriented with respect to each other so that when driven in opposite directions, their respective weights will be moving in the same generally vertical direction but in opposite generally horizontal direction, a motor having a rotary output shaft within said housing, and a chain in driving relation with said output shaft and in driving relation with said shafts, said chain having one run thereof engaged withone of said shafts at approximately the underside thereof and with the other of said shafts at approximately the top side thereof whereby said shafts may be driven in opposite directions.

14. ln a vibratory tool, the combination comprising:

a. a tool adapted to perform work when oscillated;

b. oscillatory means connected to said tool for imparting thereto oscillatory motion in generally a single direction; and

c. a mounting for one of said tool and oscillating means comprising' at least one shaft having its longitudinal axis extending in said single direction, a force transmitting support mounted for longitudinal movement on said shaft and having portions spaced along the length of said shaft, a coil spring on aid shaft intermediate the ends thereof, and spaced elements confronting opposite ends of said coil spring and positioned to be engaged by respective ones of said portions and moved therewith to compress said spring when said support is moved either way in said single direction, one of said shaft and said support being connected to one of said tool and said oscillating means.

15. A vibratory tool according to claim 14 wherein said shaft includes a reduced diameter portion intermediate its ends, and said spaced elements comprise a pair of sleeves, one at each end of said coil spring mounted for longitudinal movement on the reduced diameter portion of said shaft.

16. A vibratory tool as defined in claim 14 wherein said oscillating means includes a pair of weights eccentrically mounted on a pair of adjacent, oppositely driven, rotatable shafts with said weights being related one to the other to provide a thrust in said single direction and thus along the longitudinal axis of said first-named shaft and not transverse thereto.

fgyggg@ UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3.635.132 Dated Januarv 18. 1972 Inventor(s) William P. McIlrath: Chris Stouoraard It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r-Line 4, Cover Page, change the Assignee from "Rex Chainbelt Inc." to --Racine Federated Industries Corporation-- Signed and sealed this 13th day of June 1972.

(SEAL) Attest:

EDWARD M.FLETCHEE,JE. ROBERT GOTTSCHALE Attestng Officer Commissioner' of Patents 

1. A vibratory tool comprising a tool adapted to perform work when vibrated, vibrating means associated with said tool for oscillating the same in a predetermined direction, a mounting device adapted to be secured to a vehicle, spring means operatively interposed between said mounting device and said tool, and means for placing said spring means under compression whenever a force directed either way in said direction is exerted against the mounting device; said spring means comprising a spring having two ends and being compressible by moving one end toward the other, and said placing means comprising a first element engaged with one end of said spring means and a second element engaged with the other end of said spring means, means connected to said mounting device for moving said second element toward said first element to compress said spring means when said mounting device is moved one way in said direction and means for moving said first element toward said second element to compress said spring means when said mounting device is moved the other way in said direction.
 2. A tool according to claim 1 wherein said first element comprises a sleeve mounted for limited movement on a shaft from a stopped position toward said second element, and said second element comprises a second sleeve mounted for limited movement on said shaft from a second stopped position toward said first element; said spring means comprises a coil spring wound about said shaft and interposed between said first and second sleeves and said means connected to said mounting device both comprises abutments for engaging their associated sleeves.
 3. A tool according to claim 2 further including housing means surrounding said sleeves and said spring.
 4. A tool according to claim 2 wherein said shaft includes a center portion of reduced diameter, and said first and second sleeves are movable towards each other within the confines of said portion of reduced diameter.
 5. A tool according to claim 1 whErein there are a plurality of said last-named means symmetrically located about said mounting device.
 6. A vibratory tool comprising a tool adapted to perform work when vibrated, vibrating means associated with said tool for oscillating the same in a predetermined direction, a mounting device adapted to be secured to a vehicle, spring means operatively interposed between said mounting device and said tool, and means for placing said spring means under compression whenever a force directed either way in said direction is exerted against the mounting device; said tool comprising a compactor especially suited for use with a vehicle having a pivoted backhoe arm including a bucket cylinder and wherein said mounting device comprises a pivot adapted to be pivotally secured to the extremity of the backhoe arm; and further including connecting means secured to said compactor at a location spaced from said pivot including a flexible cable adapted to be secured to the bucket cylinder.
 7. A vibratory compactor comprising: a housing including a bottom plate adapted to engage the ground to compact the same, spring-loaded mounting means secured to the upper side of the housing and adapted to be secured to a vehicle so that the compactor may be moved along various terrain by the vehicle, and means for oscillating said housing in a generally vertical direction comprising a pair of parallel shafts within said housing and each mounting an eccentric weight, said shafts being oriented with respect to each other so that when driven in opposite directions their respective weights will be moving in the same generally vertical direction but in opposite generally horizontal directions, a motor having a rotary output shaft within said housing, and a chain in driving relation with said output shaft and in driving relation with said shafts, said chain having one run thereof engaged with one of said shafts at approximately the underside thereof and with the other of said shafts at approximately the top side thereof whereby said shafts may be driven in opposite directions.
 8. A compactor according to claim 7 further including a mounting device operatively associated with said housing and adapted to be secured to a vehicle, a means associated with said spring means and said mounting device for compressing said springs regardless of whether said mounting device is moved upwardly or downwardly.
 9. A compactor according to claim 7 further including a mounting device comprising a pivot centrally located on the top of said housing and connecting means secured to said housing at a location spaced from said pivot and including a cable adapted to be secured to a bucket cylinder of a backhoe whereby a bucket cylinder may be used to pivot the compactor housing about said pivot point to raise or lower the same.
 10. A self-leveling, vibratory compactor comprising: a compacting plate adapted to engage the ground; vibrating means associated with said plate for oscillating the same in a generally vertical direction; a mounting device adapted to be secured to a lifting arm on a vehicle; and means interconnecting said mounting device and said compacting plate including a plurality of shafts having one end connected to said compacting plate, each of said shafts having a reduced diameter portion intermediate its ends, a coil spring mounted about said reduced diameter portion, opposed sleeves abutting opposite ends of said coil spring and movable towards each other along said reduced diameter portion, and spaced abutments associated with each of said shafts and secured to said mounting device, said abutments including a first abutment for moving one of said sleeves towards the other of said sleeves when said mounting device is moved downwardly and a second abutment for moving said other sleeve towards said one sleeve when said mounting device is moved upwardly whereby said coil springs will be compressed regardless of the direction of movement of said mounting device.
 11. A self-leveling vibratory coMpactor according to claim 11 wherein said compacting plate is defined by the lower side of a generally closed housing, and said vibrating means are located within said housing and further comprise first and second, generally horizontal, spaced rotary shafts, means mounting said shafts for rotation, eccentric weight means mounted for rotation with each of said shafts and a drive motor including a rotary output shaft and a flexible, endless drive member associated with said output shaft and drivingly engaging the underside of one of said rotary shafts and the top side of the other of said rotary shafts to rotate said rotary shafts in opposite directions.
 12. A compactor according to claim 10 wherein said mounting device further includes means defining a generally horizontal pivotal mount for connection to a lift arm of a vehicle and further including means secured to said mounting device at a location spaced from said pivot mount and including a flexible cable adapted to be operatively secured to a power cylinder associated with the lift arm.
 13. A vibratory compactor comprising: a housing including a plate adapted to engage the ground to compact the same, and means for oscillating said housing in a generally vertical direction to compact the ground with which said bottom plate may be engaged and comprising a pair of parallel shafts in said housing and each mounting an eccentric weight, said shafts being oriented with respect to each other so that when driven in opposite directions, their respective weights will be moving in the same generally vertical direction but in opposite generally horizontal direction, a motor having a rotary output shaft within said housing, and a chain in driving relation with said output shaft and in driving relation with said shafts, said chain having one run thereof engaged with one of said shafts at approximately the underside thereof and with the other of said shafts at approximately the top side thereof whereby said shafts may be driven in opposite directions.
 14. In a vibratory tool, the combination comprising: a. a tool adapted to perform work when oscillated; b. oscillatory means connected to said tool for imparting thereto oscillatory motion in generally a single direction; and c. a mounting for one of said tool and oscillating means comprising at least one shaft having its longitudinal axis extending in said single direction, a force transmitting support mounted for longitudinal movement on said shaft and having portions spaced along the length of said shaft, a coil spring on aid shaft intermediate the ends thereof, and spaced elements confronting opposite ends of said coil spring and positioned to be engaged by respective ones of said portions and moved therewith to compress said spring when said support is moved either way in said single direction, one of said shaft and said support being connected to one of said tool and said oscillating means.
 15. A vibratory tool according to claim 14 wherein said shaft includes a reduced diameter portion intermediate its ends, and said spaced elements comprise a pair of sleeves, one at each end of said coil spring mounted for longitudinal movement on the reduced diameter portion of said shaft.
 16. A vibratory tool as defined in claim 14 wherein said oscillating means includes a pair of weights eccentrically mounted on a pair of adjacent, oppositely driven, rotatable shafts with said weights being related one to the other to provide a thrust in said single direction and thus along the longitudinal axis of said first-named shaft and not transverse thereto. 